Operational amplifiers having a differential output require an accurate common-mode feedback loop in order to set the common-mode output voltage of the amplifier. The basic principle of operation for a common-mode feedback circuit is that the common-mode voltage is sensed and compared to a reference thereby generating a difference or “error” signal. The error signal is fed back into the main amplifier, and the common-mode of the amplifier is set equal to the reference voltage, and consequently, the error is eliminated or substantially reduced.